More than 50 years later, a Nazi blockade of the Netherlands has yielded evidence that a mother's nutritional status during pregnancy may correlate with her offspring's risk of developing schizophrenia.

A team led by Dr. Ezra Susser, associate professor of clinical psychiatry and epidemiology at P&S and the New York State Psychiatric Institute, used food rationing and health outcomes records kept by the Dutch during the so-called Hunger Winter and for decades afterward to arrive at findings published in the January 1996 issue of Archives of General Psychiatry. The Hunger Winter occurred from October 1944 to early May 1945, when the Nazis established a blockade in retaliation for the Dutch underground's support of an Allied invasion (the invasion was the subject of the movie "A Bridge Too Far"). The blockade resulted in a severe famine, the peak of which occurred during the last three months of the period. Using the dates of birth to estimate the dates of conception, Dr. Susser found that individuals who were conceived during the peak of the famine had twice the risk of developing schizophrenia as individuals conceived either in the early months of the famine or after it ended.

At the peak of the famine (February through April 1945), malnutrition was the leading cause of mortality, and fertility rates were down by 50 percent. Typical rations for the period were well below 1,000 calories a day, consisting of a potato, a piece of bread, and a sugar beet, for instance, for one person. Anecdotes from the time indicate that in addition to attempting to supplement these rations with food from the black market, people turned to eating tulip bulbs or putting paper in their soup.

"The study could turn out to have important preventive implications for at least some forms of schizophrenia," says Dr. Susser. "The most likely explanation is that a nutritional deficiency is involved, perhaps of a micronutrient." Dr. Susser compares the current state of knowledge about schizophrenia and nutrition to recent research that confirmed that folic acid deficiencies in early gestation can cause neural tube defects. "Until recently we knew very little about the causes of neural tube defects, except that they run in families-which is similar to what we know now about schizophrenia. But then a series of observations, animal and human, began to link neural tube defects to prenatal nutritional deficiency. After only a few decades of work, we now know for sure that we can significantly reduce the risk of neural tube defects by providing folic acid supplements in early pregnancy."

Dr. Hans W. Hoek of the Netherlands collaborated in the Dutch Hunger Winter investigation. The study was based on data collected by Dr. Zena Stein and Dr. Mervyn Susser, Dr. Ezra Susser's parents, who demonstrated in 1974, in their landmark book on the Dutch famine, that prenatal starvation in early pregnancy caused pre-term birth, excess infant deaths up to three months, and excess obesity in young adults but not, as believed, deficits in intellectual performance.